Our prior application referenced above describes fibrous ceramic insulation materials formed by dispersing a suspension of ceramic fibers over a form-defining surface, drying the fibers to form a mat, solidifying the mat by soaking it with a sol-gel ceramic precursor, and gelling and curing the sol-gel precursor. The present invention is directed to an improvement to achieve improved mechanical strength, a lower dielectric constant and more isotropic properties as compared to the fibrous ceramic of our prior application.